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Feb. 9, 1932. H. s. DAvls ET A1.. v

PROCESS FOR GENERATING TERTIARY ALCOHOLS Original Filed Feb. 24

uw SP. Mu. m5) W 5 f 0c J QN m M Patented Feb. 9, 1932 autres f HAROLDs. Davis, or antracite, AND amanecer. emanan or assioma, Messebausnrrs,Assrenores, DY Masiva assrenmnnrs, 'ro ra'raonaoaa @Hamont convene#TIoN, or New Yoan, N. r., A cosoaarron or Dmawam: f

PROCESS FOR, GENERATING TERTIRY .ALCOHOLS riginal application ledFebruary 24, 1925. Serial No. 10,992, and in Germany February 23,11926.Divided and this application led March 28 1930. Serial No. 439,656.

'lhis application is a division of parent application, Serial No.10,992, filed February 24, 1925.

This invention relates to the preparation, segregation and utilizationof oletine hydrocarbons and to the production of their derivatives,including alcohols and other useful substances. The oleines may bederived from such materials as petroleum, peat, c'oal, oil shales` andlike earboniferous natural materials by cracking or pyrogenesis, socalled.

The olefine mixtures produced by heating such substances to temperaturesresulting in pyrogenetic transformations are, as is well known,exceedingly complex` generally containingr ethylene, propylene,butylenes, amylencs, hexylenes and higher olctines ofthe general formula(Elim, Unlike saturated h vdrocarbons` olefines are capable of readilyreacting or combining with reagents, including1r the polybasic acids (ofwhich snlphuric acid or phosphoric acid are typical) the halogens andhalogen compounds, hypochlorous and other acids.

The reaction of sulphuric acid with the olefines has been known sinceits discoveryin Faradays laboratory in 1826. and alcohols have beenprepared from alkyl sulphuric acid f products of this reaction oncertain olefines hy hydrolysis and distillation by numerousinvestigators since Berthelots research in 1863. Derivatives of oleiineshave been made on a commercial scalen this country b v tirst preparingan acid reactive liquor of sulphuric acid with oil gas since as early as1906 (American Ether Company ot Richmond, Virginia; l. Fritzsche,Zeitschrift iur angewandte Chemie, 1896, pp. 456, 459; Die Chemischelndustrie, Vol. 35, p. 637, 1912). Gases produced in the liquid phasecracking of petroleum have been similarly treated for the recovery otalcoholic mixtures including,r

isopropyl, secondary butyl and amyl nico- These treatments, so Jfar asWe are hols. aware. have been of a kind adapted to the incidentalrecovery at gas works or petroleum pressure stills of `rases fromcracking; operations rarely containing more. than 12% of olefines, andfree from-any substantial contents of very reactive highly crackedhydrocases not feasible.

cai-bons such as the diolefines. Whenl any attempt' has been made toproduce industrially from mixed oleine bearing gases, such as t ie Wastegases from liquid phasecracking, acid reactive liquors capableof'hydrolysis and distillation to lobtain alcohols, sulphation has beencarried out, so far as We are aware, by reaction upon the Whole gaseousmixture with acid of a degree of concentration selected to reach a`result necessarily in the nature of a compromise between destruction bypolymerization or otherwise of the more reactive olelines, andincomplete sulphation; and hence, with partial recovery only of therealizable olefine values and with high acid consumption. Such processesare economically justifiable only when lean gases are available in greatquantities otherwise Wasted. They are not so j ustiiable when the gas tohc treated is rich in olelines so reactive as to be converted intopolymers while making the oleine-acidv compound of a less reactiveremainder. When the olefine bearing gas is rich in highly reactiveoleines, a singie-stage treatment to obtain acid products cannot bepractised; the reaction of the more highly reactive oleines and other hdrocarbons to' polymer under treatment w1th acids capable of formingaddition compounds with the less reactive oletines is too vi orons and'too productive of heat to permit t iis even in the case of relativelylean gases.

rlhe known procedure has therefore been to destroy the very reactableolelines in one lot ot acid, and sulphate the remainder in another lotof acid.

lf it were practicable to obtain mixed. alkyl acid compounds and otherderivatives of the rich gases, such as result from vapor phase crackingdirected to the production of oleines, by a group reaction With acid,the result Would not be desirable. rlhe did'crent alcohols, at leasteight in number, resulting from hydrolysis of the obtainable compoundshave boiling points ranging from 80 to 14()Q C., and separation fromeach other is in most The uses of these alcohols (e. g. isopropyl andamyl alcohols) are Widely divergent, and to produce them in`7 Elimadmixture would be commercially undesirable.

This process provides a treatment of oleiine hydrocarbons, liquid orgaseous, particularly mixed hydrocarbons resulting from as symmetricalmethyl-ethyl-ethylene, and other unsaturated bodies having a highreactive affinity for combining acids or, other reactants, and alsocontaining other olefines of a lower order of reactivity toward the saidcombining agents; for example, propylene, isopropyl, ethylene,but'ene-l, butene-2, pens tene-l and pentene-Q.

This new process thus provides a mode of treatment applicable tohydrocarbon products rich'in highly reactive'or unsaturated olenes torecover valuable derivatives and segregate the oleines substances in theorder.

of their chemical activities toward reagent substances, for examplepolybasic acids; and whichwill permit the separation production,severally or in groups, of olefine compounds, suchas the oleine-acidcompounds capable of hydrolysis or other after-treatment and separation,leading to separate production of the consequent different alcohols orother olene derivatives. An object attained by the process is theseparation of complex oleine mixtures, especially mixtures rich in ole-`fines, into fractions substantiallypaccording to the order of themolecular weights of their principal contents, and the treatmentseverally of these fractions for the optimum production of valuablederivatives, e. g. the appropriate alcohols, in a relatively pure andunmixed state; and without substantial destruction at any stage of thisseparation of any of the several fractions at the respectiveJ stage ofthe operations.

The process conservesfor use at a further stage of the process such ofthe reactive oleines as are not concerned at any stage of the process inthe reaction contrived and intended to produce a particular derivativeor intermediate. The recommended procedure comprises a stage or stagesof separation of a fraction or fractions of the material contain- .ingthe oleine or olefine groups to be recovered, followed by treatmentselectively to vdifferentiate and segregate the component olenesubstances in accordance with their respective and relative chemicalreactivities.

In general it may be stated that the preferred raw material containsmore than 30% of unsaturated hydrocarbons.

It is advantageous, in the practice of this process, to proceed upon abasis of known is the constant and controllable mixture produced by theprocess described in the application for Letters Patent by Earl P'.Steven-- son and Clarence K. Reiman, Serial No. 8,907, filed February13, 1925, which comprises subjecting vapors of a petroleuin'or afractional distillate of petroleum, for example ,gas oil, so called, toheat during flow in a tubular 'lli retort heated at successive zonesthereof to differing degrees, with the eil'ect of maintaining the vaporsat a nearly constant cracking temperature during a substantial time ofHow, this constant temperature being such as to result in optimumdevelopment of olene values. For this purpose, a cracking temperaturemaintained nearly constant at a selected value between 600 C. and 650 C.during a suilicient time of flow to produce from 1000 to 1700 cubic feetof gaseous product per barrel o f 42 gallons passed produces,

satisfactory material for this treatment.

The preferred vapor-phase cracking tem eratures are higher than thosehereto ore known for the commercial production of motor spirit, which donot exceed 500 C., so far as I am aware (Lewes, Journal Society ofChemical Industry, Vol. XI, page 585) and are not such high temperatures(700 to 10000 C.) as are used for making oil gas by the known methods ofPintsch, 'Fritzsche or Ullman. y

The invention will therefore now vbe described as carried out upon thegaseous ef-v fiux of vapor phase cracking of petroleum so contrived asto roduce a vaporous` and gaseous efflux whic i, when stripped of amotor spirit fraction, is exceedingly rich in the olefne substancesabove mentioned. But

it will be understood that this process is api plicable without cha-nge,except in degree, to

the treatment of other complex oleine mixtures, and that the specificinstances now to described are described by way of illustration of theinvention, and are not to be viewed as comprising every instance ofpractice according to the invention.

In the accompanying drawing, the ligure is a diagrammatic flow sheetshowing a preferred assemblage of apparatus illustrative of certainphysical stages of separation of the material treated.

The process to be described comprises, in general, submitting theoleine-bearing gases to treatment for the physical separation ofvfractions containing groups of olefine substances capable of chemicalsegregation concomitantly with the formation of olefineacid compounds,emulsions, or solutions,

:all

Leiten under conditions permitting the segregation severally ofderivatives, hols resulting from hydrolysis of these compounds.

Referring to the drawing, a container 1 for the supply of oil maydeliver to a'feed stock reservoir 2, whence by a suitable pressuredevice 3 the material is forced into a preheater or primary vaporizer 4(preferably a suitable tubular coil) and through a superheatcr orsecondary vaporizer may be substantially the same, kind of tubularheater as the primary preheater 4. Between the preheater 4 andsuperheater 6 the flowing stream, already substantially all va.- por,may be subjected to treatment adapted to separate out the inclusions oflow volatility, and pass on the vapors and gases. A liquid separator 5,preferably of a kind operating without substantial loss of heat, isrecommended. Collected liquids from this sepa ator may flow through apipe G and ac001- er (l to tar storage tanks 10.

Vapors superheated at (l pass to a cracking tube 7. The effluent gases,vapors and suspensions fron'i cracking are recommended to be treated ina separator 8, which'may work on the cvclonic or centrifugal principle,and deliver its liquid separates into the pipe 6, and its vaporous andgaseous elilux into the bottom of the first of a series of separatingand condensing towers', for example, the tower 1l, adapted tocounter-current low in contact of the vapors and gases and thecondensate from tower 12, which in turn is adapted to counter-currentflow of the vapors and gases and the condensate` from a fractionatingcondenser 13 of any suitable reflux type.

The tower 12 is preferably a fractionating tower of the bubble type.From the bottom is taken a relatively heavy fraction which is deliveredinto the top of tower 11, wherein it serves to condense and wash out anyheavy and undesirable tars formed in the cracking reaction. From one ofthe lower plates of this tower is drawn olf a fraction of substantiallythe same boiling range as the feed stock, but as this will, ofnecessity, contain some hydrocarbons in the motor spirit range, itcannot be returned to the feed stock without n'iaterially decreasing theyield of motor spirit. Provision is included, therefore, fOr strippingthis fraction of its lighter hydrocarbons, such as a fractionating tower12, which is heated at the base at 14 and delivers overhead the desiredfraction of its feed into one of the top plates of tower 12. Thestripped cycle-stock is delivered through a pipe 14 and cooler C to thefeed stock tank. 'lhe overhead from 13 is cooled at 18, and thecondensate at this point is crude motor spirit in ther preferredoperationlgof tower 12.

The vaporous elluent from condenser 18 is nowr fractionally condensed orabsorbed,

for example alco- Y G, which or otherwise treated to separate olenefractions, which from their prcponderant contents may be described as anamylene fraction, a butylene fraction, and a gaseous fraction rich inpropylene and ethylene, and hereinafter referred 'to as a propylenefraction. For example, the gaseous elluentfrom condenser 18 may bedelivered through meter M and scrubbed in absorption towers 20 and 21 bya counter-current flow of cool absorption oil stored in tank 23,delivered by a pump P1 through a cooler C2 and pipe 24 to the top'oftower 21, to receiver 25, through a cooler tl" to the top of tower 20,and the saturated oil delivered through a pipe 2G to a storage tank 27,whence the saturated oil may flow through a heat exchanger 28, pipestill 29 and vaporizer 30 to a relluxing tower 31. from which theliquids may be led through cooler C4 to the crude motor-spirit orgasoline storage tank 16 pipe 32. Unvaporized absorption oil fromvaporizer 30 may flow through pipe 30, heat exchanger 28, and cooler C5to tank 23.

The vaporous effluent ati33 may -bc delivered through a condenser 34 anda sepa'- rator 35, whence the vapors pass to a compressor 3G andpressure storage tank 37. Condensates-at 34, 35 and 37 may be deliveredto tank 17, the pressure and temperatures being such as to provide atthese points liquid .fractions corresponding to thc amylcne-fractionfluid in tank 17. Pressure tank 37 may deliver` if desired. through asuitable reduction valve 39 to gas-holder 40, in which are collected theresidual gases from the saturated scrubbing oil. This' gaseous fraction.if so separated, represents substantially the major portion of thebutylene hydrocarbons, whereas the residual gas from tower 21, collectedin the holder 22, contains the propylene and i ethylene. y

When appropriate conditions are realized in and pr'ior to flow throughthe cracking tube 7, the, respective fractions capable of beingseparated by steps of condensation or absorption are sharplycharacterized by the desired preponderance (amounting under goodconditions to substantial freedom from mixture with each other) of theolefine substances sought to be collected and separated. Any suitablecondensation or absorption fractionating treatment may therefore beresorted to, and the apparatus mentioned may be varied in accordancewith engineering preferences.

y Under preferred conditions, cracking in the tube 7 is at. a relativelyconstant temperature at or about (S00o (l, to 6150 C.

The following typical example of operation of the vapor phase crackingprocess above described and the segregation of the olefines intocomparatively simple fractions shows the pumped at P2,

grelative amounts involved and the quantity l of each fraction:

Results of ft2-hour run (quantities per barrel,

(a) up to 25 4.51 lbs.

(b 2 to 45 C 5.151115.

9. But iene fraction (gaseous) 19.6 ibs. (181 cu. ft.)

Lig t naphtha (included in 2) 11.35 lbs.

These results are from separation by compression, distillation andcondensation. When the absorption step, as described above, is resortedto, typical results are as follows:

Feed atoc1o -32-34 B. gas oil (from South Texas crude). Feed rate- 1bbl. per hour per six\inch cracking tube. Temperatures- Va orizer 632 C.maximum Tu 601 C. (average) Tube sections (averages) Entrance 2 3 4 -5 6595 C. 602 C. 602 C.. 603 C.- 606 C. 603 C. Conversions per bbl.passed'- Process gas (sp. r. 1.055) 1035 cu ft. Oil scrubbed gas sp. gr.0.929) 675 cu. It. Butylene fraction (non-condensed gas fromdistillation of saturated absorption oils) (sp. gr.-1.52) 102 cu. ft.Amylene fraction (condensbles recovered by fractionation to 60 C.) 2.6gallons Crude na htha` (condenslbles between 6 and 210 9.3 gallons Cyclestock (condensibles above 210 C. 19 gallons Tar residues 2.1 gallonsOlefne content of gaseous fractona= Process gas oleiines above ethylene35.1 Oil scrubbed gas olenes above ethylethylene 75.7

Vapor phase cracking ot the preferred practice having been carried onattlie temperatures mentioned, the products are chiefly unsaturated,being` largely olefines with some naphthenes and aromatic hydrocarbons,together with almbst negligible amounts of saturated or paraiiinhydrocarbons, particularly in the lighter liquid fractions. The oleiinecontent of the gas prior to compressing or oil scrubbing to removecondensibles olefines.

may be as high as 54% by volumein the operation of an appropriate vaporphase cracks ing process, comparison, still gases '1s vthe olefinecontent of pressure-l seldom higher-than 10%, and

'is usually under 8%, justifying designation as lean gases.

The aggregatechemical character of these two classes of olefine mixturesis likewise quite diierent, so that steps for the recovery ofderivatives applicableto the lean gases are not applicable to thericher'mixtures. The oleines in pressure-still gases have a highproportion of normal oleines, and do not contain substantial amounts ofthe very reactive, highly cracked hydrocarbons, such as the di- Therecommended steps above described, for which other procedures may ofcourse be substituted within the invention so lon as the results areproduced, result ina ractionation of the oleines as follows:

` y K Boiling points==` Ethylene 103 C.

Gaseous Propyleiie 48.4 C. Iso-butylen 6 C. Butylenes-. Butene-1 5 C.Butene-2 +1 C.

Bolling points= Isopropy1ethy1ene 21 C. v Unst m1. methyl-ethyl- 31 t33h c e yens o Liquid Amylene Periferie-2 Trimethyl ethy1ene 37 to 42 C.Pentene-l 39 to 40 C. Hexylencs 55 to 7 5 CL Higher oleinesv up t0 150C.

yof conditions or procession of reagent substances by which any wholemixture of these gaseous substances can be treated to yield insuccession the derivatives of the unsaturated hydrocarbons present inthem in amounts constituting 'valuable sources of materials vneeded forindustrial uses. But We have nevertheless determined that the substancesare reactive with the polybasic acids, for example sulphuric acid, in acertain order, ethylene being the least reactive as follows:

Boiling points State 1. Ethyiene CHFPH. 103 c. Gas 2. PropyleneCH3-CH=CH2 48.5 C. Gas 3. Pentene-l CH3-CH CH2 CH=CH1 39-4() C. Liquid4. Pentene-2 CH3-C 2 CH=CH CH3 36 C.(741mm.) Liquid 5. Butene-l CH3 CHgCH-= CH2 5 C. v Gals p11' in s0- u on 6. Butene-2 CH5 CH=CH CH3 1 C. Gasor in so- 7. Isopropyl ethylene CH A mon ?Cia-CH=CH2 21.1 c. Liquid CH8. Uns mmetrical methyl ethyl CH:

et ylene C=CH2 31 to 33 C. Liquid CHB CH 9. Trim th l eth iene CH CB:

e y y o=o 37 to 42 c. Liquid CH3 I H I b t l n CH 10 s0- u y e e s C=CH26 C. Gas or in sointimi for example that described. For

- appreciable absorption of ethylene and the absorption of propylene isvery rapid, but the yield ol" isopropyl alcohol will be small due to theexcessive polymerization when and if the gas treated contains the morereactive olelines in the amountsin Which they naturally OCCUT.

The following causes may be responsible for this phenomenon:

(l) The reactive olefines evolve' so much heat on contact with thesulphuric acid that localoverheating occurs Which tends to polymerizeall the dissolved products including propylene.

(2) The reactive olefines combine with the sulphuric acid more rapidlythan propylene and decrease the ability of the acid to absorb thelatter.

(3) 100% sulphuric acid can easily act as an oxidizing agent toward thereactive olelines and the Water evolved dilutes the acid and lowers itspower to absorb olefines.

Per contra, if the gas is treated with acid of a strength adapted toabsorb trimethyl ethylene and of the proper strength and under theoptimum conditions to absorb the olenes which yield tertiary derivatives(Nos. 8, 99 l0 above) there is no substantial absorption of the lighterand simpler oleiines such as propylene. For a quantitative idea of thegreat variations in reactivity manifested loy these oleines towardssulphuric acid, isobutylenc isseveral hundred thousand times as reactiveas ethylene.

In the case ot isopropyl ethylene, which so far as We are aware hasnever, previous to the research leading to this invention, beenconverted into an alcohol through reaction With sulphuric acid, acids ofsuiiicient strength to absorb pentene-l and pentene-2 quantitativelypolyinerize isopropyl ethylene at temperatures below 30 C. Highertemperatures and more concentrated acid than this are required to absorbthe other oleiines for the results desired, and the conditions forsecuring' a ,good yield of amyl alcohol from this particular olenesubstantially polymerize the other olenes except ethylene and propylenepresent in this mixed gas.

By theY fractionatinu` procedure above delscribed we have avoided anynecessity to subject to sulphuric acid absorption all of the react-iveolefincs at once, and any necessity for producing alcohols incapable ofbeing subsequently separated.

By processes extending and developing the results of this invention,some of which are the work of others and no part of this invenproducedfrom the vapor-phase cracked hytion, at least eight dierent alcohols maybe' drocarbons, having a boilingv range extending If these were producedconjointly it would be impractical subsequently to separate them, and asthe uses (of isopropyl and amyl alcohols, for example) are Widelydivergent, such a mixture would be of little( or no commercial value. Asa specific example of this diflicultytwo pairs of alcoholsthat cannot beseparated by frictional distillation are:

Iscnftpyalcohol (constant boiling nilxture) boiling point Tertiary butylalcohol-boiling point 79.92 '0.- Tertlary amyl alcoholboiling range101.6 to

1oa c. Secondary butyl alcohol-boillng point 99.5 C.

The processing of the total oleines presentin a cracked petroleumproduct to secure ltertiary as Well as secondary derivatives calls for afurther departure from the art as practiced Where tertiary derivativesare not. re-

covered. The usual procedure is to moderately dilute the product fromsu'lphuric acid absorption with Water and then distill. rl`he point towhich this dilution must be carried to avoid destruction by the actionof the sulphuric acid on the alcohols during distillation varies withthe diderent alcohols but in the case of secondary alcohols there islittle hazard in distilling from 25% acid solution. Tertiary alcohols,however, behave quite differently and tertiary amyl alcohol, forexample, cannot safely be distilled from even a one per cent solutionWithout substantial decomposition. lhe preferred procedure forrecovering tertiary alcohols from admixture with sulphuric acid is toneutralize as with lime and distill from a neutral solution. vlt will beobvious that this procedure is not practical when applied tol a complexsulphuric acid product containing small percentages of tertiary bodiesas compared tor secondary bodies. lt becomes practical and feasible whenthe tertiary bodies are concentrated and segregated as in the practiceof this invention. v

The procedure above described, to avoid the difficulties .and providethe advantages I'ust adverted to, separates the material into groupscapable of bein reactedupon preferi entially in res ect to t eirconstituent members, thus ena ling separations of the acid combinationswith the constituent members ot these groups severallyi So for as thereis advantage in separating them, these groups are:`

'(1) rlhe gaseous fraction containing ethy- Iene and propylene.

(2) rl`he butylene fraction containing isobutene and butene-l orbutene-2 or both of the initial 10W-boiling distillate fraction, and

( 3) The residue of the condensate which I may contain each of the veisomeric amylenes With varying amounts of hexylenes and higher oleiines.

Fraction (l) may now be treated in accordance with the specific relativeproperties of its constituents. Because this fraction will containtraces of diolefines andolefines more reactive than propylene, owing tothe practical and obvious limitation of any system for physicalfractionation, it is desirable to treat this fraction iirst withsulphuric acid, by tower scrubbing, of a strength that will selectivelyreact upon the olefines (more reactive than propylene) therein present.In the preferred procedure this fraction is first scrubbed with acid of8084% strength and is then subjected to the action of sulphuric acidhaving a concentration from 95 to 100% at a temperature preferably belowC., whereupon propylene is substantially absorbed.

` The ethylene remains relatively unaffected quantities as impurities,either remain in the.

gaseous state, as in the case of methane or A ethane, or remainuna-bsorbed by the acid treatments; or, as in the case of acetylenes,areconverted into heavy compounds readily separable from the remainder,as by fractional distillation. If present, such bodies are not` found inimportant quantites, and the resulting polymer is a heavy oily compound,of relatively uniform characteristics. In practice Withhydrocarbonmixtures obtained as herein described the proportional amounts both ofsuch extraneous gaseous products and of the heavy oily poylmer resultingfrom acidtreatment are relatively small.

Upon hydrolysis of the acid compounds l severally obtained as described,under suitable conditions, as by the addition of water or steam, anddistilling at corresponding temperatures, ethyl and isopropylalcoholsrespectively may be recovered in the distillates, leaving a residue of,substantially alocoholfree sulphuric acid.

The butylene fraction (2) capable of economic use contains butylenesdifficult to separate from each other by distillation. Of these butene-land butene-Q are less reactive chemically than iso-butylene'.Derivatives of butene-l and butene-2 as a consequence oftheintramolecular structure -of these substances have a secondary molecularformatiomwhereas derivatives of iso-butylene have a tertiary structure.This may ilow from the structure of iso-butylene, conceived, as acentral carbon bond being a double bond. As for example,

the addition ofwater (H2O) produces a tertiary alcohol having thestructure:

Preferred procedures therefore comprise reactingupon the butylenefraction in the order of reactivity of these component substances, toform in several succession tertiary and secondary derivatives.

For example, the butylene fraction containing isobutene, butene-l` andbutene-2 (all gaseous) is passed through sulphuric acid of aconcentration of 60% more or less in such manner as to effect asintimate a contact between the gas and the acid as possible, for thepurpose of absorbing isobutene. Recommended apparatus comprises aninterru ted flow tower with glass or other inert pac ing arranged forcounter-current flow of gas and acid. Isobutene is very highly reactive;va satisfactory differential absorption is practicable at all ordinarytemperatures. The isobutene is here selectively absorbed, leaving thebutene-l and butene-2 and'other gases, if any, which are then conductedthrou h sulphuric acid of la concentration of o, more or less, by whichthe butene-l and butene-2 are substantially absorbed. One of theadvantages of this procedure arises from having removed the substancesreacting to tertiary compounds, sin'ce the reaction of thesecondary-alcohol-forming substances with stronger acid for theirconversion evolves heat of lesser degree, and the natural riseoftemperature, for example to 40 C., may be permitted to take place,unless acid more concentrated than 80% is resorted to, in which case itmay be desirable'to hold the temperature down to a point below 15 C.These reactions' are preferably carried out in a tower similar to thetower just mentioned one tower may be. used if arrangement is made tocollect the gaseous ellux and repass it, supplying the more concentratedacid on the second passage and separately collecting the liquid effluxfrom the first and the second passage.

The liquid from the first of said steps c'ontains the isobutene eitherabsorbed in the acid or in the form of tertiary butyl alcohol byauto-hydrolysis in the dilute acid; this may be further diluted forcomplete hydrolysis and the alcohol distilled therefrom. Preferably thedilute liquid is neutralized with an alkali before distillation, toresult in a much higher yield of the tertiary butyl alcohol by avoidanceof reaction with the acid during distillation. v

The liquid from the second step of treatment contains the butene-l andbutene-2, and this liquid may be diluted for complete hydrolysis intothe secondary butyl alcohol, and

i thereafter distilled without neutralization to obtain a high yield ofsecondary butylv alcoas hydrocarbons of the group Cnllgm.

Lemmi sired, by any usual or customary Water-absorbent chemicaltreatment, such as treatment with lime or caustic,

The amylene fraction (3) whether collect ed by absorption as describedor by pressure condensation and fractional distillation of (a) up to C.-(b) a5 to 45 o. (c) above C.

Since the lower or more volatile olelines have been substantiallyremoved as above described, distillate (a) consists primarily ofisoproypl ethylene, distillate of pentenel, pentene-Q, unsymmetricalmethyl-ethylethylene, and trimethyl ethylene, and distillate (c)contains the hexylenes and heavier or higher boiling olefnes.

T he amylene fraction (8) can be treated with sulphuric acid in stages,or the fractions (a) and (Zn) can be processed separately and .with someadvantage.

Distillate (a) contains redominant quantities of isopropyl ethy ene.rl`he specific treatment of thisdistillate forms no part of ourinvention herein claimed.

ln order to secure substantial yields of all alcohols derivative fromthe mixed amylenes of fraction (t) it is desirable te remove thehydrocarbons of the group Cnllgm and any still less saturatedhydrocarbons) which may be present. Either alternative processes issatisfactory at this stage.

lt has been found, for example, that by treating this fraction firstwith concentratedv hydrochloric acid, the amylenes `which areconvertible into tertiary derivatives are substantially converted intochlorides Which. owing to their'relatively high boiling points, can vbeeasily separated from the unchanged amylenes. The resulting mixture ofchlorides on hydrolysis, carried on preferably with the addition of limeor caustic soda, yields tertiary alcohols.

`We do not herein claim the specific method of recovery with the aid ofhydrochloric acid treatment.

of Water to isobutene, trimethyl, ethylene, un-" symmetricalmethyl-ethyl-eth, iene and probably some of the higher ole nes whileconcurrently edecting the polymerization of diolefines and thosehydrocarbons of a lesser degree of saturation than the olefines intoheavy,.oillil{e polymers which, on account of diversity of boilingpoints, may be separated by fractional distillation, or other appro--priate means, from the unchanged olenes.

As the result of this preliminary reaction, Vfor example either the saidhydrochloric or sulphuric acid treatments, a highly refined amylenefraction remains after treatment, which fraction is substantially amixture of isopropyl ethylene, pentene-l and pentene-Q, and which doesnot contain, appreciable amounts of the other olefines, though there isno disadvantage in the presence of substantial amounts of the normalbutylenesand heXylenes at this sta e, since these olefines are of thesame order o. activity as the amylenes therein present, and theirderivatives can easily be se arated from those of the amylenes byfractional distillation.

Addition of sulfuric acid of a concentration of 77% more or less/5tothis refined amylene causes absorption with concurrent formation of thecorresponding intermediates ofthe alcohols from which the correspondingalcohols may be recovered by dilution and distillation. f

'lo further illustrate the advantage of this invention We have treatedthe rich gas from vapor phase cracking as described, without firstremoving the amylene fraction, with 95% acid. rlhe result was anevolution/of excessive heat, rendering control diliicult, if notimpossible, and the recovery of small amounts only of secondaryalcohols, and no tertiary alcohols. rllhere were also formed largequantities of heavy tar-like polymers. By lirst removing the olefineshigher than propylene We have successfully used filming sulphuric. acidas an absorbent for the re- 'mainder, obtained in alcohol yield of 40%of the Weight of acid used, and minimized the polymer formation to underof the alcool producedo For specific exam, les of treatment of theamylene fraction 3, We have obtained the following results:

Example I From the processing of 32 B. gas oil under the conditionsmentioned for example above, there is obtained 2.6 gallons of amylenefraction condensibles recovered by fractionation to C.) per barrelpassed. The preferred treatment-of this fraction and its results are asfollows:

To the 2.6 gallons of amylene fraction We rst add .12.2 lbs. ofsulphuric acid under conditions of thorough agitation keeping themixture preferably below 20 C., and 'continue this treatment over aperiod of 6 hours as a maximum, adding the acid in two equal portions at3 hour intervals. At the end of this period agitation is stopped and themixture allowed to settle for a time sumgli lll@

or acid layer, which is carefully neutralized with caustic anddistilled, preferably through a fractionatino' column, cutting when thetemperature reaches 100 C. at the top of the column. Under thesespecific conditions we recovered in thisexample .28 gallons of crudetertiary alcohols per 2.6 gallons of amylene fraction treated.

i as

The residual hydrocarbons from this treatment to recover tertiaryalcohols are distilled through a fractionating column from a slightlyalkaline mixture, and the distillate up to C. is segregated and treatedfor conversion into secondary alcohols.

Starting with 2.6 gallons of amylene fraction, there is recovered 1.1gallons of hydrocarbons boiling up to 60 C. which are now treated with77% HgSO., in two portions, each of .55 gallons or 7.65 lbs. In thisstage the temperature is allowed to rise to 35 C. and maintained atunder 40 C. preferably, and agitation is continued over a total periodof six hours. The mixture is then allowed to settle and the lower oracid layer is drawn oi, diluted with water to bring the concen trationof acid below 20%, and then distilled until practically all of thealcohol is carried over. The distillate consists of two layers, a

lower or water layer and an upper or alcohol layer. From the 2.6 gallonso amylene fraction at the start of this processing, there is recoveredunder the above specic conditions .56 gallons of crude secondaryalcohols.

Secondary and tertiary butyl alcohols are successfully recovered fromthe butylene fraction by first scrubbing with more or less sulphuricacid, and then with 77% more or less sulphuric acid, as above de-Example I I Concurrentl with the production of 2.6 oallons of emy enefraction there is recovered 102 cu. ft. of butylene fraction as setforth in the example above of a typical vapor phase cracking operation.As stated, this fraction can be absorbed under pressure or by cooling orboth in the amylene fraction ;'or it can be treated separately toproduce tertiary and secondary butyl alcohols. The following is anexample of separate treatment:

The butylene fraction is rst scrubbed or treated with a relativelydilute sulphuric acid, vfollowed by more concentrated acid.

We have obtained satisfactory results by using in the lirst absorptionstage 65% acid and in the second 77% acid. The -amount Vof acid requireddepends upon the physical efiiciency of the absorption apparatus`employed in large measure; using even comparatively ineicient apparatus,an acid eiciency can be realized wherein three pounds of acid(,calculated as 93%) produces one pound of alcohol.

From the treatment of 100 cu. ft. of the butylene fraction hereindescribed, we have' produced .28 gallons of tertiaryand .46- gallons ofsecondariy)7 alcohols. f

During the a sorption of the butylene in the treatment for tertiaryalcohol with the particular reagents mentioned above we prefer to keepthe temperature below 20 C., and during the secondary stage at about 35C. As in the case of the tertiary' amyl alcohol, it is necessary todistill the tertiary butyl alcohol from a neutral or slightl alkalinesolution to secure the highest yiel s, though tertiary butyl is notsubject to decompositlon in acid distillation in the same degree astertiary amyl alcohol. i

Wherever in thisl specification particular concentrations of acidreagent substances adapted to oleiine absorption are alluded to, it willbe understood according to the com mon knowledge of the numerouschemists familiar with the behavior of acids toward olefines for nearlya century, that the acid concentration is relative to the respectivelymentioned or to normal temperatures, and that at different temperaturesanother concentration of acid is equivalent, within those limits atwhich the action of the acid reagent ceases to become an absorption, andenters upon the destructive formation of the compounds herein alluded toas polymers.

For the operations of fractional treatment with I-IZSO., e. g. of theamylene fraction (b), werecommend the use of apparatus comprising achamber adapted to be heated or cooled, and equipped for mechanicalyagitation of its contents; adapted for the slow feed of acid of theappropriate concentration; suitable settling vessels for decantingloffthe unchanged residue of the materials of lesser reactivity; andappropriate vessels for acid reaction upon'the decanted residue.Distillation of the oleine-acid liquors may proceed in appropriate steamstills. In essentials, the units of apparatus required are familiar inthe practice ofthe chemical industries, one of the' advantages of thisinvention resides in the relatively simple nature of the instruments andoperations required.

We claim:

1. In the process of generating tertiary alcohols of 4 and 5 carbonatoms to the mole-V cule from a mixture of hydrocarbons produced bycracking petroleum oil and containing both secondary and tertiaryolenes, the steps ofseparating from said mixture by distillation afraction, the olene content ofwhich consists predominantly of secondaryAand tertiary olefines of the same number of' and y.

contained in said fraction is accomplished by contacting said fractionwith aqueous sulphuric acid of not exceeding 65%, HzSO, content.

3. Process according to claim 1, in which the selective sulphation oftertiary olefines contained in said fraction is accomplished bycontacting said fraction with aqueous sulphuric acid of not exceeding65%, H2SO4 content, at temperatures not exceeding C.

4. In the process of generating tertiary alcohols of 4 and 5 carbonatoms to the molecule from a mixture of hydrocarbons produced bycracking petroleum oiland containing not less than of unsaturatedhydrocarbons including both secondary and tertiary oletines, the stepsof separating from said mixture by distillation a fraction, the olefinecontent of which consists predominantly of secondary and tertiaryoleines of the same number of carbon atoms to the molecule correspondingto the alcohol selected, and selectively sulphating the tertiaryolefines contained in said fraction.

5. Process according to claim 4, in which the selective sulphation oftertiary olefines contained in said fraction is accomplished bycontacting said fraction with aqueous sulphuric acid of not exceedingH2SO4 content.

6. Process according to claim 4, in which the selective snlphation oftertiary olefines contained in said fraction is accomplished bycontacting said fraction with aqueous sulphuric acid of not exceeding65%, H2SO4 content, at temperatures not exceeding 20 C.

In the process of generating tertiary alcohols of 4 and 5 vcarbon atomsto the molecule from a mixture of hydrocarbons produced by vapor phasecracking of petroleum oil and containing not less than 30% ofunsaturated hydrocarbons including both secondary and tertia-ryolefines, the steps of separating from said mixture by distillation afraction, the olefine content of which consists predominantly ofsecondary and tertiary olefines of the same number of carbon atoms tothe molecule corresponding to the alcohol selected, and selectivelysulpliating the tertiary olefines contained in said fraction.

8. Process according to claim 7, in which the selective sulphation oftertiary oleines contained in said fraction is accomplished bycontacting said fraction With aqueous sulphuric acid of not exceeding65%, H2SO4 content. v

9. Process according to claim 7, in which the selective sulpliation oftertiary olenes contained in said fraction is accomplished by contactingsaid fraction with aqueous sulphuricvacid of not exceeding 65%, ILS()4content, at temperatures not exceeding 20 C. 10. In the process ofgenerating tertiary Ybutyl alcohol from a mixture of hydrocarbonsproduced by cracking petroleum oil and containing secondary and tertiaryolenes, the steps of se arating from said mixture by distillation araction, the olefine content of which consists predominantly ofsecondary land tertiary oletines of 4 carbon atoms to the molecule, andselectively sulphating the tertiary olciines contained in said fraction.

11. Process according to claim 10, in which the selective sulphation oftertiary olefines contained in said fraction is accomplished b Ycontacting said fraction with aqueous sulplulric acid of not exceeding65%, HZSO; content. i

l2. Process according to claim 10, in which the selective sulphation oftertiary oleines contained in said fraction'is accomplished bycontacting said fractionivith aqueous sulphuric acid of not exceeding65%, HzSO., content, at temperatures not exceeding 20 C.

13. In the process ofgenerating tertiary butyl alcohol from a mixture ofhydrocarbons produced by cracking petroleum oil and containing not lessthan 30% of unsaturated hydrocarbons including'both secondary andtertiary olelines, the steps of separating from said mixture b vdistillation a fraction, the ole- ,tine content of which consistspredominantly of secondary and tertiary olefines of 4 carbon atoms tothe molecule, and selectively sulphating the tertiary olefines containedin said fraction.

14. Process according to claim 13, in which the selective sulphation oftertiary olefines contained in said fraction is accomplished bycontacting said fraction with aqueous sulphuric acid of not exceeding65%, HESO., content.A

15. Process according to claim 13, in which the selective sulphation oftertiary olefines contained in said fraction is accomplished bycontacting said fraction with aqueous sulphuric acid of not exceeding65%, H2504 content, at temperatures not exceeding 20- C.

16. In the process of generating tertiary butyl alcohol from a mixtureof hydrocarbons produced by vapor phase cracking of petroleum loil andcontaining not less than 30% of unsaturated hydrocarbons including bothsecondary and tertiary olefines, the steps of separating from saidmixture by distillation a fraction, the-olefine content of whichconsists predominantly of secondary and tertiary olelnes of 4 carbonatoms to the molecule, and selectively sulphating the tertiary olefinescontained in said fraction.

17. Process according to claim 16, in which the selective sulphation oftertiary olefines contained in said fraction is accomplished bycontactingsaid fraction with aqueous sulphuric acid of not exceeding65%, H2804 content.

18. Process according to claim 16, in which kthe selective sulphation oftertiary oleines contained in said fraction is accomplishedby contactingsaid fraction with aqueous sullphuric acid of not exceeding G5VI%,IH,SO.

content, at temperatures not exceeding 20 C. 19. In the process ofgenerating tertiary alcohols of from 4 to 5 carbon atoms to the lmolecule from a mixture of hydrocarbons 'produced by cracking petroleumoil and con.

' taining both secondary and tertiary oleines,

the steps of separating from said mixture by distillation a fraction,the olefine content of which consists redominantlyof secondary andtertiary ole nes of the same number of carbon atoms to the moleculecorres onding to the alcohol selected, and selective y separatingtertiary olefnes from the said fracn tion.

20. HIn the process of generatingl tertiary butyl alcohol from a mixtureof ydrocarbons produced by cracking petroleum oil and containingsecondary and tertiary oleines, the steps of separating from saidmixture by distillation a fraction, the olefine content of whichconsists predominantly of secondary and tertiary olefines of 4 carbonatoms to the molecule, and selectively separating tertiary olefines fromthe said fraction.

HAROLD S. DAVIS. Y WALLACE J. MURRAY. l

